The structure of the active site of plasma amine oxidase will be investigated, as well as the mechanism of action of the following suicide inhibitors of PAO: CH2NH plus 3 - COO phi CH2BrCH2NH plus 3. The interaction of dioldehydrase with a coenzyme analogue in which one of the propionamide group has been replaced by -OCH3 will be investigated. The detailed mechanism of the non-enzymic reaction of CN minus with carboxymethyl-B12 will be studied. The mechanism by which gamma-cystathionase is inactivated by HC xi- CH-CH2-CHNH plus 3-COO minus will be investigated. Bibliographic references: Riceberg, Louis, J., Simon, Marcia, Van Vunakis, Helen, and Abeles, Robert H. Effects of Aminoacetonitrile, an Amine Oxidase Inhibitor, on Mescaline Metabolism in the Rabbit. Biochem. Pharmacol. 24, 119 (1975). Valinsky, Jay E. and Abeles, Robert H. The Formation of Underated Propionaldehyde by Dioldehydrase. Arch. Biochem. Biophys. 166, 608 (1975).